d1 and d0 are two decimal digits. Each of them is one of 0, 1, 2, 3, 4, 5, 6, 7, 8, or 9. If a number n ends with two digits d1 and d0, this means that there exists an s such that n = 100*s + 10*d1 + d0. E.g., a number 123 ends in 2 and 3. This means that 123 = 100*1 + 10*2 +3.